This invention relates to a heat exchanging apparatus, and more particularly to a refrigerant evaporator or condenser for use in, for example, an automobile air conditioner.
Heat exchanging apparatus, such as the serpentine type heat exchanger, is well known as suitable for use in automobile air conditioners as the evaporator or condenser. A prior art serpentine type heat exchanger is illustrated on FIGS. 1 and 2 which show the evaporator.
The evaporator comprises a flat tube 1 which has a multichannel internal construction formed with a number of parallel channels (not shown) and is bent into the form of a serpentine tortuous cross section. One end of flat tube 1 is brazed to an inlet pipe 2 which comunicates which a decompression or expansion means (not shown) in a refrigerating circuit. Therefore, refrigerant flows from inlet pipe 2 into the channels of flat tube 1 and flows from the outlet of outlet pipe 3 into the compressor. A corrugated fin unit 4 is disposed between each of the adjacent or opposed upright portions of flat tube 1, the unit being securely joined to such portions by brazing along their horizontal lines of contact. A protective plate 5 is securely joined by being brazed to each of the corrugated fin units 4 which are joined to the outermost upright portions of flat tube 1, respectively.
In an evaporator with the above-described construction, flat tube 1 as shown on FIG. 2 has the upright portions facing one another connected by an arcuately curved section 1b. For this reason, the corrugated fin unit cannot be disposed within the arcuately curved section 1b. Thus almost all of the air passing through the space within this arcuately curved section 1b moves through without heat exchange with the refrigerant. The efficiency of heat exchange is therefore undesirably reduced.
One solution for solving the above problem is to cover the arcuately curved sections 1b with an air shield plate 6 (FIG. 2) which is integrally formed with a cooling case to prevent the air-flow from passing through the space within arcuately curved sections 1b. However, the air space which is covered by shield plate 6 becomes unavailable space for heat exchange. Therefore, the space efficiency of the heat exchanger, i.e., the ratio of the area which is usefully heat exchanged with air to the volume of the heat exchanger, is reduced.